Deferred-action battery



Nov. 23, 1965 F. soLoMoN ETAL Re 25,913

2 Sheets-Sheet 1 39 INVENTORS.'

FRA/VK SULOMO/V ROBE/'77' l'.' ENTE/YS Nov. 23, 1965 F. soLoMoN ETAL Re-25,913

DEFERRED-ACTION BATTERY Original Filed July 15, 1959 2 Sheets-Sheet 2INVENTORS F RANK SLO/HAN ROBERT/z' ENTERS United States Patent O 25,913DEFERRED-ACTION BATTERY Frank Solomon, Lake Success, N.Y., and Robert F.

Enters, Hackensack, NJ., assignors to Yardney International Corp., NewYork, N.Y., a corporation of New York Original No. 3,100,164, dated Aug.6, 1963, Ser. No.

826,589, July 13, 1959. Application for reissue Dec. 1l), 1963, Ser. No.339,568

2 Claims. (Cl. 136-90) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specilication; matterprinted in italics indicates the additions made by reissue.

The present invention relates to electrochemical batteries of thedeferred-action type.

Deferred-action batteries generally comprise a plurality of individualcells, each formed by at least one positive and at least [on] onenegative electrode in a charged state, in combination with activatingmechanism designed to inject liquid electrolyte into the cells inresponse to extraneous signals. It is desirable that the injection ofthe electrolyte into the cell assembly be as rapid as possible so thatthe full power of the battery is available when needed.

When the cells are connected in parallel, instantaneous activation isonly a minor problem since the entire electrode assembly can beirrigated through a single channel from a common source. Withseriesconnected cells, on the other hand, care must be taken to avoidthe possibility of short circuits by the electrolyte liquor itself. Forthis reason it has heretofore been the practice to provide each cell ofsuch battery with an individual casing and to fill these casings throughrespective branch channels from a common manifold. Channel systems forthis description tend to be bulky since the passages must be largeenough to prevent clogging by dust or loose electrode material.

It is, therefore, an object of the present invention to provide asimplified series battery of the deferred-action type in which the abovedisadvantages are avoided.

A more specific object of this invention is to provide means for rapidlyirrigating an assembly of dry-charged, series-connected cells via acommon channel yet in a manner minimizing the flow of discharge currentover electrolytic leakage paths between adjoining cells.

A further object of this invention is to provide improved means forventing a cell assembly of the character referred to, so as to expeditethe admission of electrolyte liquor into such cell assembly.

The foregoing objects are realized, in accordance with a feature of thisinvention, by the provision of a stacked cell assembly whose individualcells each consist of a positive electrode, a negative electrode, and auintervening separator of sufficient porosity to absorb an electrolyteliquor introduced edgewise `into the separator. The exposed edgeportions of the separator layers of the several cells, which terminateat the feed channel for the electrolyte, alternate with strips of asuitably hydrophobic insulating material whose surface is not readilywetted by the electrolyte; these strips shield the incoming liquor fromthe edges of the cell electrodes and, together with the interveningseparator edges, define all or part of the feed channel which in anadvantageous embodiment passes centrally [of] through the cell assembly.

The interposition of non-wettable zones between the electrolyte inletsimpedes, in a passive manner, the formation of a liquid film within thefeed channel capable of passing substantial discharge currents betweenadjoining cells. This action can be supplemented, in accordance withanother important feature of the instant invention, by the provision ofmeans for actively breaking up any fluid ice bridges that maynevertheless have formed in the channel, such means preferably takingthe form of a jet of air or other gas injected into the channelimmediately after the introduction of the electrolyte liquor. This gasjet, which may be released by the activating signal to exert thenecessary driving pressure upon the electrolyte, acts to force liquorinto the pores of the separator while simultaneously purging theresidual liquor from the feed channel.

The far end of the separato-r, i.e. the edge opposite the one facing thefeed channel, may be exposed to the atmosphere at one or more locationsin order to provide, iu accordance with still `another feature of theinvention, vents for the air expelled from the separator pores by theelectrolyte.

Since some liquor will unavoidably seep out through these vents at theend of the activation process, it is desirable from the viewpoint ofleakage suppression that their area be small compared with the overallsurface area of the electrode assembly which, except for the said vents,is encased in a shell of insulating material. Preferably, pursuant to amore specific feature of the invention, the separator layers of theseveral cells are provided with tabs projecting into the venting holesof the shell so as to provide a continuous outer surface whilefacilitating the expulsion of air from the interior of the shell.

The negative electrode of one cell and the positive electrode of anadjoining cell may be combined into a single bipolar plate member,thereby further increasing the co-mpactness of the assembly. Suchbipolar member may comprise a highly conductive backing plate, eg. ofsilver or copper, to whose opposite faces the respective activematerials are applied by some suitable process, eg. `by spraying,sintering, or electrodeposition. Reference in this connection may bemade to co-pending application Ser. No. 825,842, now abandoned, tiled onJuly 8, 1959, by Kenneth N. Brown and Otto Wagner, in which a processfor the electrolytic production of a bipolar electrode has beendisclosed and claimed.

The above and other objects, features and advantages of this inventionwill become more fully apparent from the following detailed descriptionof certain embodiments, reference being made to the accompanying drawingin which:

FIG. 1 is a section through a battery assembly according to thisinvention;

FIG. 2 is a perspective view (parts broken away) of the battery assemblyof FIG. 1;

FIG. 3 is a sectional top view of a modified battery yassembly accordingto this invention; and

FIG. 4 is a sectional elevation taken on line 4 4 of FIG. 3.

As shown in FIGS. 1 and 2, a battery 10 comprises a cylindricalinsulating shell 12 of suitable potting material, such as an epoxyresin, which is scaled `at its ends by a pair of metal elements 13 and14 and surrounds a cell assembly 11. The cell assembly 11 consists of aplurality of positive electrodes 16, a like number of negativeelectrodes 17, and interelectrode separators 18 interposed therebetween.Each of these elements 16, 17, 18 is in the shape of a thin circularwafer with a centrally located orifice which forms part of a feedchannel 19. The electrodes 16, 17 are combined in pairs into bipolarelements by being bonded, as by electro-deposition, onto respectivefaces of a common support 21 of highly conductive material such ascopper or silver. Among the positively charged materials useful to formthe electrode layers 16 there may be mentioned silver oxide or peroxide,copper oxide, nickel oxide or lead peroxide. The negative layers 17 mayinclude zinc, cadmium, lead or magnesium. The concentric edges of eachbipolar cell unit 16, 17, 21 are encased by washers 24 and 2S ofelectrolyte-repellent material.

The electrolyte for the electrochemical couples listed above may bealkaline or acidic and, with silver-zinc or silver-cadmium couples, mayconsist of sodium, potassium or lithium hydroxide, with or withoutspecial-purpose additives. The washer elements 24 and 25 may be made oftluocarbon resins or epoxy resins.

The interelectrode separator 18 consists of a porous insulating materialhaving capillary attractions for the electrolyte. Suitable materials forsuch separator include cellulosic felts, wettable synthetic fibers andglass wools, or combination thereof.

The inner circular edge of each separator layer 18 projects towardschannel 19 `between adjacent washers 24. The outer circular edge of eachseparator, projecting between washers 2S, rests against the inner wallof shell 12, except at isolated locations where this shell is providedwith apertures to accommodate tabs 18' which are integral extensions ofthe separator layer and project outwardly through these aperturestowards the atmosphere. The entire stacked cell assembly is packedtightly inside the casing 12, 13, 14 so as to be under some initialpressure even prior to the introduction of the electrolyte.

The lower end element 14 is in the form of an inverted cup, defining acompartment 37, and is provided with an external lug 14 to which theterminal 15' is attached. Feed channel 19 communicates with compartment37 through a hole 14 in end element 14, a guard plate 38 extendingoutwardly from hole 14" to form an abutment for a bladder 39 whichcontains a charge of electrolyte 40. This bladder 39 is clamped in placebetween an inner shoulder on cup 14 and a cover member 31 which closesthe compartment 37. The cover 31 is provided with an apertured boss 31connected to a source of compressed gas (not shown) via a tube 36.Opposite the outlet of this tube, at the orifice 14, there is provided apoint 32 adapted to pierce the bladder 39 when the latter is deflectedfrom its normal, illustrated position by the pressure of gas admittedthrough tube 36; it will be understood that the upper wall 39 of bladder39 is stretched taut enough across the width of compartment 37 so as notto be deflected towards point 32 by impact or gravity during normalhandling of the battery assembly.

In operation, the battery is activated by the entrance of the compressedgas into the compartment 37 by way of tube 36, this gas having beenreleased from its container by a suitable electrical or mechanicalactivating device (not shown) responsive to an extraneous signal. Thegas, pressing upon the bladder 39, first causes the upper bladder wall39 to flex against point 32 so as to be ruptured thereby. This causesthe liquid 40 to be expelled and driven, by the continuing gas pressure,into the feed channel 19 where it is virtually instaneously absorbedinto the pores of the separator layers 18. The air previously entrappedin these pores and in channel 19 is driven out, ahead of the liquid,through the apertures in shell 12 occupied by the separator extensions18'. As the plate 3S guides the final quantity of the electrolytethrough the orifice 14", the lower bladder wall 39" approaches the point32 and is finally also ruptured thereby, thus enabling the gas from tube35 to sweep into the channel 19 and to clear the channel walls of anyadherent electrolyte particles. Naturally, the gas supply should be soregulated at this point that the gas pressure drops to a levelinsufficient to drive the electrolyte out of the shell assembly by wayof the separator tabs 18'; some liquid may, neverthless, emerge at theseseparator extensions and form leakage paths between dilferent cellseparators without, however, seriously affecting the operation of thebattery since the conductivity of these leakage paths will necessarilybe extremely limited.

FIGS. 3 and 4 illustrate a battery 50 differing from battery of FIGS. land 2 by being prismatic rather than cylindric. Positive electrodes 56,negative electrodes 57 and separators 54 are arranged in the previouslydescribed manner to form an assembly 51 consisting of a plurality ofseries-connected unit cells. Assembly 51 is maintained under someinitial pressure in a casing 52 whose top and bottom plates 53, 53'carry terminals 55, 55'. Casing 52 may again consist of a potting resinor other suitable insulating material.

At opposite locations, preferably along the minor sides of therectangular cross section of the battery assembly 50, the casing 52 isrecessed to form narrow vertical channels 66, 69 around limitedperipheral portions of the cell assembly 51. As is clearly shown in FIG.4, washers 60 of electrolyte-repellent material shield the electrodes56, 57 and their supporting plates throughout the minor sides of therectangle and in particular in the region of channels 66 and 69. Betweenthese washers 60, tabs 62, 63, project from the separators 54 into thechannels 66, 69. An inlet tube 70 at channel 66 serves for the admissionof an electrolyte, followed by a stream of flushing gas, in order tosaturate the separators 54 with liquid in the manner previouslydescribed, the liquid being taken up by the tabs 62 while the airexpelled from the interstices of the separator escapes through the tabs63 into the channel 69 and vents through an outlet 71 into theatmosphere. The activating procedure is thus essentially the same as inthe preceding embodiment.

The separator S4 has been shown composed of two layers S4', 54" of whichthe layer 54' lies next to the negative electrode 57 and advantageouslyconsists of absorbent paper whereas the layer 54 is made of a moreporous material such as glass wool. This combination insures rapidpenetration of the separator by the electrolyte liquor whilesufliciently preventing any galvanic contact between adjacent electrodesof opposite polarities. It will be understood that the presence of thchydrophobic washers 60 prevents the formation of objectionable leakagepaths in either the feed channel 66 or the venting channel 69.

From the foregoing disclosure it will be apparent that there has beenprovided an improved mechanism as well as a novel process for activatinga dry-charged battery by inroduction of a liquid electrolyte into a feedchannel, absorption of the electrolyte from such channel by wicklikeelements, e.g. separators, in the various battery cells, and subsequentllushing of the feed channel by a gas stream. The invention is, ofcourse, not [lmited] limited to the specific embodiments described andillustrated but may be realized in various modifications and adaptationswithout departure from the spirit and scope of the appended claims.

We claim:

1. An electrochemical battery of the deferred-action type, comprising ahousing a plurality of stacked drycharged bipolar silver-zinc electrodesin series in said housing each separated from an adjacent bipolarelectrode `by an electrolyte-absorbing separator, a plurality of ventsin said housing respectively disposed adjacent saidelectrolyte-absorbing separators [,1; a centrally disposed feed channelfor the admission of liquid electrolyte into tlie electrolyte-absorbingseparators, said electrolyte-[absorbent] absorbing separatorsterminating at said feed channel and being adapted to draw electrolytefrom said feed channel and]; elcctrolytc-repelling spacer means boundingsaid feed channel between said electrolyteabsorbing [spacers] separatorsand encompassing said bipolar electrodes whereby electrolyte isprevented from electrically connecting the component electrodes of saidbipolar electrode along said feed Cleannel; a rupturableliquid-electrolyte-containing reservoir disposed adjacent the [said]slack of electrodes cutting means disposed adjacent said rupturablereservoir and adapted to rupture the same, and means for applying gaspressure to said reservoir to bring the same into cutting contact withsaid cutting means whereby the electrolye is released from saidreservoir and is forced into said centrally disposed feed channel.

2. An electrochemical battery of lli@ deferred-action type, comprising ahousing; a plurality of stacked drycharged bipolar electrodes in seriesin said housing each separated from an adjacent bipolar electrode by anelectrolyte-absorbing separator, the positive material of said electrodebeing silver and the negative material thereof being selected from thegroup which consists of zinc and cadmium; a centrally disposed feedchannel for the admission of liquid electrolyte into theelectrolyte-absorbing separators, said electrolyte-absorbing separatorsterminating at said feed channel and being adapted to draw electrolytefrom said feed channel; electrolyte-repelling spacer means bounding saidfeed channel between said electrolyteabsorbing separators andencompassing said bipolar elec'- trodes whereby electrolyte is preventedfrom electrically connecting the component electrodes of said bipolarelectrode; a rupturable liquid-electrolyte-containing reservoir disposedadjacent the stack of electrodes; cutting means disposed adjacent saidrupturable reservoir and adapted to v rupture the same, and means forapplying gas pressure to said reservoir to bring the same into cuttingContact with said cutting means whereby the electrolyte is released fromsaid reservoir and is forced into said centrally disposed feed channel;and venting means in said housing open toward said separators atlocations opposite said feed channel for permitting the escape of airfrom said separators as said electrolyte is supplied thereto.

References Cited by the Examiner The following references, cited by theExaminer, are of record in the patented le of this patent or theoriginal patent.

UNITED STATES PATENTS 690,770 1/1902 Reed er a1. 136-87 2,594,879 4/1952Davis 136*90 2,639,306 5/1953 Fishbach 136-112 2,754,428 6/1956 Depoix136-111 2,798,111 7/1957 Renke 136-90 2,847,494 s/1958 Jeannin 136-902,352,592 9/1958 sa1auze 136-90 2,886,621 5/1959 Henman 136-90 2,988,5876/1961 Haring 136-90 FOREIGN PATENTS 1,093,523 5/1956 France.

WINSTON A. DOUGLAS, Primary Examiner. MURRAY TILLMAN, JOHN H. MACK,Examiners.

